Several Cymbopogon species are called turpentine grass, including C. excavatus (broad leaved turpentine grass) and C. plurinodis (narrow-leaved or bushveld turpentine grass), either of which may be the species in picture.  

Both are unpalatable, poor grazing grasses because of a bitter taste; both occur widely across Africa and South Africa. Turpentine grass often grows along roadsides.

This grass is used for thatching